Reliable performance of in-space propulsion systems is dependent both on the reliable ignition and combustion of propellants and on the stability of thruster materials under extreme conditions. Our research investigates the physical chemistry aspects of satellite propulsion performance using a variety of experimental and theoretical techniques. Experimental methods such as infrared spectroscopy, mass spectrometry, thermal methods (high-pressure calorimetry and thermalgravimetric analysis), and materials analysis (electron microscopy, surface area, pore size distributions, etc.) can give important insights into the factors contributing to performance losses. Theoretical approaches include density functional theory, quantitative structure-property relationship and Gaussian processes/active learning methods, molecular dynamics, and chemical kinetics with computational fluid models. One such example is the development of various multi-physics modeling and simulation tools to model both the reactive flow in the monopropellant thruster and the heat transfer through the housing. Understanding the chemistry involved in propellant ignition and combustion will lead to more reliable and higher-performing propellant development. Similarly, understanding the factors contributing to materials degradation in the extreme conditions in space thrusters will help to mitigate these issues. The combination of higher performing propellants and more robust thruster materials will ultimately lead to longer propulsion system lifetimes in space, a major goal of the Space Force. 

 

References

1)      Zhou, W.; Liu, J.; Chambreau, S. D.; Vaghjiani, G. L., “Formation and fragmentation of 2-hydroxyethylhydrazinium nitrate (HEHN) cluster ions: a combined electrospray ionization mass spectrometry, molecular dynamics and reaction potential surface study.” Phys. Chem. Chem. Phys., 25, 17370-17384 (2023).

2)      Chambreau, S. D.; Popolan-Vaida, D. M.; Kostko, O.; Lee, J. K.; Zhou, Z.; Brown, T. A.; Jones, P.; Shao, K.; Zhang, J.; Vaghjiani, G. L.; Zare, R. N.; Leone, S. R., “Thermal and Catalytic Decomposition of 2-Hydroxyethylhydrazine and 2-Hydroxyethylhydrazinium Nitrate Ionic Liquid.” J. Phys. Chem. A., 126, 373-394 (2022).

3)      Zeng, H. J.; Khuu, T.; Chambreau, S. D.; Boatz, J. A.; Vaghjiani, G. L.; Johnson, M. A., “Ionic Liquid Clusters Generated from Electrospray Thrusters: Cold Ion Spectroscopic Signatures of Size-Dependent Acid–Base Interactions,” J. Phys. Chem. A, 124, 10507 (2020), cover article.

key words

ionic liquids; heterogeneous catalysts; green propellants; rocket propulsion; computational fluid dynamics; chemical kinetics; molecular dynamics; machine learning

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral and Senior applicants

Additional Benefits

Relocation

Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.

Health insurance

A group health insurance program is available to awardees and their qualifying dependents in the United States.